The invention relates to fluid filters, and more particularly to direct flow filters.
The invention arose during continuing development efforts relating to direct flow filters. The filtration industry, including for automotive application, is driven towards more efficient space utilization, e.g. eliminating large open areas within a filter element and/or a filter housing between the filter element and the housing, which is particularly desirable in space constrained areas such as behind the cabin or under the hood of vehicles. Direct flow filters are effective for this purpose. A direct flow filter filters fluid flowing along an axial flow direction and includes a pleated filter element having a plurality of pleats defined by wall segments extending along a transverse direction between first and second sets of pleat tips at first and second sets of axially extending bend lines, the transverse direction being perpendicular to the axial direction. In a direct flow filter, fluid to be filtered flows axially into the channels, parallel to the noted bend lines. In contrast, in a transverse flow filter, fluid to be filtered flows across the pleats, transversely to the noted bend lines.
In the filtration industry, embossing is a common practice to maintain pleat spacing in a filter element. Standard embossment patterns have not been effective in a reduced size direct flow filter because of the flow direction. Furthermore, the pleat depth in a direct flow filter is typically greater than that in conventional or transverse flow filters.
The present invention provides improvements in direct flow filters. In one aspect, channel width is maintained, to provide higher capacity. An effective embossment pattern is provided for maintaining channel width, including as a dust cake begins to form on the filter element media. The embossment pattern provides support as the dust cake continues to build, and prevents collapse of the pleats which would otherwise cause the pressure drop to increase at a rapid pace. The invention provides a desirable flow pattern, reducing turbulence and allowing dust cake formation at a uniform distribution along the filter element.